Newsletter <= 9.4.0 - Unauthenticated Stored Cross-Site Scripting via 'np1' Custom Field Parameter

Summary

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'np1' Custom Field Parameter in all versions up to, and including, 9.4.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The subscription endpoint (na=sa) requires no nonce, no capability check, and no CAPTCHA, and the payload can be smuggled past email-address validation by embedding the {profile_1} placeholder in the local part of the submitted address, since WordPress's is_email() permits curly braces there.

Timeline

1. Oct 2, 2026, 7:39 AM UTCCVE published
2. Oct 3, 2026, 3:34 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 3, 2026, 3:42 PM UTCRecord last updated

Affected versions

• satollo Newsletter – Send awesome emails from WordPress

  through 9.4.0

References 9